Yeah, "site:" still works. I use "site:reddit.com/r/edh $cardname" any time I want to research Magic the Gathering combos. It also works far better than the same search string in DDG/Brave/Bing.
There should be an inverse, "nosite:" selector, to avoid results from a site.
negation works with site operator
You can use -site: to negate it. Pretty neat
Yep, negation does work. Do -site: rather than site: